End bell construction



END BELL CONSTRUCTION Filed Aug. 3, 1950 W xqum Patented Mar. 16, 1954 UNITED STATES PATENT OFFICE.

END BELL CONSTRUCTION Application August 3, 1950, Serial No. 177,452

3 Claims.

The present invention relates to a rotor construction and particularly to the end bell for an axial flow compressor rotor.

In order to withstand the thermal stresses set up in the end bell as well as the stresses set up by the differential expansion between the end bell and the adjacent rotor disc, it has previously been customary to make the end bell extremely heavy providing a rigid structure by which to engage and clamp the end disc of the rotor against the remaining discs. A feature of this invention is an arrangement of the end bell such that the weight may be materially reduced without afiecting the ability of the end bell to carry the load imposed thereon.

Another feature of the invention is an arrangement of the end bell with a substantially clyindrical flange concentric to and substantially the same diameter as the flange on the rotor disc engage-d thereby such that the cylindrical flange may be relatively thin and thereby capable of expansion or contraction with the adjacent disc.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a sectional view longitudinally through a compressor showing the end bell construction.

Fig. 2 is an enlarged sectional view of the end bell.

Fig. 3 is a fragmentary sectional view along the line 3-3 of Fig. 2.

The invention is shown in a multistage axial flow compressor having a casing 2 supporting a number of rows 4 of stationary vanes extending radially inward from the casing. The vanes alternate with rows of blades 6 mounted on the periphery of the compressor rotor 8. In the arrangement shown the rotor is built up of a number of separate discs each carrying one row of the blades 6 with the discs arranged in stacked concentric relation and held together by a centrally located through bolt l2 extending between the end bells and I6 located at opposite ends of the rotor. Each disc ID has laterally extending flanges I8 concentric to and spaced from the axis of the disc and engaging at their end surfaces with the cooperating flange on the adjacent disc to provide the proper axial spacing of the discs and to form in effect a blade supporting cylinder by the axial alignment of all of the flanges l8. The adjacent flanges may have radially extending face splines 20 thereon to aid in piloting the discs and to transmit torque between adjacent discs.

The endmost disc has a projecting flange 22 on the outer side of each disc for engagement with the end bell and each end bell has a cylindrical flange 24 or 26 in alignment with the cylindrical sleeve portion 28 of the end bell ad jacent to the rotor discs has a heavy radially extending flange 34 with the outer periphery of which the cylindrical flange 24 is made integral. The radial flange especially the surface facing the ad acent disc preferably slopes away from the disc, as shown. With an arrangement of this character the radial flange of the end bell which is approximately the same diameter as the annular flange on the disc is made heavy enough to withstand the axial loads developing thereon during the operation of the compressor but the cylindrical flange forming the connection between the radial flange on the end bell and the adjacent disc is such that expansion of the disc is not impeded by the end bell and the intermeshing face splines are not caused to slide radially relative to one another thereby possibly causing galling. The cylindrical flange extends at a substantial angle, approximately a right angle, to the radial flange, as will be apparent, and the intersection between the flanges is abrupt as shown. The radial flange is preferably tapered toward its outer edge to be substantially a constant stress type of flange, and the cylindrical flange carrying primarily compressive stresses may thus be thinner than if it were loaded in bending.

The hub portion 28 of the end bell is substantially smaller in external diameter than the cylindrical flange 24, and the end of the hub portion projects within the cylindrical flange. The radial flange 34 projects outwardly from the end of the hub portion adjacent to the compressor disc and has its opposite side surfaces converging in a radially outward direction such that the flange is relatively thick at the hub and tapers to a substantially thinner dimension adjacent its outer edge. The side surface of the radial flange remote from the adjacent disc extends in a substantially radial direction and the opposite side surface, as above stated, slopes away from the adjacent disc in a radially outward direction. At the junction of the radial and cylindrical flangesa relativelyheavy ring 35 is formed for the purpose of more uniformly distributing the stresses from the cylindrical flange 24 into the radial flange 34.

To assist in piloting the discs with respect, to, one another and with respect to, the end bells, the rotor may have in radial alignment with each intermeshing row of face splines a sleeve or ring 36 which, as best shown in Fig. 2,, has. its outer corners notched as at 3 8 to engage with cooperating shoulders 40 on the flanges l8 and 24 to support the sleeve in such a manner that it cannot move axially within the rotor. It will be apparent that assembly of the rotor in an arrangement of this type is relatively simple since the discs may be arranged in stacked relation one on another, being piloted by the face splines and by the rings 36. until the "rotor and the end bells are all assembled.

The through bolt may then be placed in position and clamped up tight by a suitable nut (not shownl thereby clamping the entire rotor elementsinto a'rigid assembly. The through bolt may e. r n d a de i d n erb e Eatent No; 3,461,212. With the flanges it} located at a substantial distance from the axis f.- the btor. s appa t at, a b ant i..,. y mpar ed totho rot r the eb m ni,- lee bend n r n he op ra ion, f th d vice- It is ro e understo d hat t e n t on s, not,

limited tc the specific embodiment herein illusat d nd es ed but may be u d, i ther a sw i out d par e from t pir a defi edv th l win cla ms,

What, is claimed: is:

1. In. a rotor construction, at least one disc. haying a row, of blades, on, itsiperiphery and have.

ing a central opening, an end bell at. each side.

of; thediscand a through bolt extending between he. nd. bells. for holding. the disc and end, bells inassembled, relation, said, disc having any 311111171, lar flangeon oneside surface thereof concentric t andspacedfifom the axis of. the, disc and also spaced from the opening in the, disc, one of, said.

endbellshaving a cylindrical flang thereon cor-,7 responding in diameter tothe flange on. the disc such that the flange is relatively thick at itscon-,

nection to thehub portion and tapers. to a suo. stantially, thinner axial; dimension adjacent its outer. edge, the, side surface of; theradial flange remote from the adjacent disc being substantially dia andz ho p os e do ur aceoi; he rad a an e o n awa om, he ad c nt... d c, in

a radial direction outwardly from the axis of the end bell, the cylindrical flange extending at an abrupt angle to the radial flange at its periphery.

2. In a rotor construction, at least one disc having a row of blades on its periphery and having a central opening, an end bell at each side of the disc and a through bolt extending between the end bells for holding the disc and end bells in assembled relation, said disc having an annular flange on one side surface thereof concentric to and spaced from the axis of the disc and also spaced from the opening in the disc, one of said end bells having a cylindrical flange thereon corresponding in diameter to the flange on the disc for endwise engagement between the flanges when the rotor is assembled, said end bell also including a central hub portion substantially smaller in diameter than the cylindrical flange and concentric thereto, and a radially extending flange integral with said hub portion and said cylindrical flange, said radial flange having its opposite side surfaces converging in a radial direction outwardly from the axis of the end bell such that the flange is relatively thick at its connection to the hub portion and tapers to a substantially thinner axial dimension adjacent its outer edge, the side surface of the radial flange remote from the adjacent disc being substantially radial, and the opposite side surface of the radial flange sloping away from the adjacent disc in a radial direction outwardly from the axis of the end bell, the cylindrical flange extending at an abrupt angle tothe radial flange at its periphery, and a ring at the junction of the cylindrical and radial flanges and integral with both, said ring being relatively. thicker than the cylindrical flange.

3. In a rotor construction, at least one disc, having a row of blades on its periphery and hav.. ing a central opening, an end bell at each side of the disc and a through bolt extending between the end bells for holding the disc and end bells in assembled relation, said disc having an annular flange on one side surface thereof concentricto and spaced from the axis of the disc and also spaced from the opening in the disc, one of said end bells having a cylindrical flange thereon corresponding in diameter to the flange on the disc for endwise engagement between the flanges, when the rotor is assembled, said end bell also. including a central hub portion substantially smaller in diameter than the cylindrical flange; and concentric thereto, the end, of the hub portion adjacent to the disc being radially surrounded by the cylindrical flange and a radially extending flange integral with said hub portion and said cylindrical flange, said: radial flange projecting radially from the end of the hub adjacent to the disc, and said radial flange having its opposite sidesurfaces converging in a direction away from the axis of the end bell such thatthe flange is relatively thick at its connection to the hub and tapers to a substantially thinner axial dimension adjacent. its outer edge, theside surfaceof the radial flange remote from theadr jacent disc being substantially radial and the opposite side surfacesloping away from, the.ad-., jacent disc. in a radial direction outwardly from the axis of the end, bell, thev cylindrical flange extending at an abrupt angle to the radial flange, the end of the hub adjacent to the-disc and the;

end of thecylindrical flangewhionengageswith,

the annular flange on the disc lying substantially Number in the same radial plane. 2,369,051 HARTFORD NATIONAL BANK AND 2,452,782 TRUST COMPANY, 2,479,046 By GREELY STURDIVANT, 5 2,548,386

Trust Oflicer, Executor of the estate of Andrew V. D. Willgoos,

deceased.

352,282 References Cited in the file Of this patent 10 900,402 UNITED STATES PATENTS 937533 Number Name Date 2,356,605 Meininghaus Aug. 22, 1944 Name Date Huber Feb. 6, 1945 McLeod Nov. 2, 1948 Ledwith Aug. 16, 1949 Howard Apr. 17, 1951 FOREIGN PATENTS Country Date Germany Apr. 24, 1922 France Oct. 2, 1944 France Mar. 8, 1948 

